Yawning has an unexpected influence on the fluid inside your brain
Summary
New Scientist reports that yawning and deep breathing have different effects on cerebrospinal fluid (CSF) movement in the brain, revealed by MRI scans. The study with 22 healthy adults found yawning can move CSF and venous blood in the same direction, boosting carotid inflow by over a third and producing a unique yawning signature in tongue movement. Researchers note several possible functions—from waste clearance to thermoregulation—though the exact mechanism remains unclear; contagious yawning was used to trigger the responses.